Apparatus for grinding or polishing flat glass



June 7, 1955 Filed Jan. 25

R. TOUVAY APPARATUS FOR GRINDING OR POLISHING FLAT GLASS 1951 3Sheets-Sheet 1 Inventor June 7, 1955 TQUVAY 2,709,875

APPARATUS FOR GRINDING OR POLISHING FLAT GLASS Filed Jan. 25, 1951 3Sheets-Sheet 2 WM Inventor way/(4 By June 7, 1955 R. TOUVAY 2,709,875

APPARATUS FOR GRINDING OR POLISHING FLAT GLASS Filed Jan. 25, 1951 sShets-Shee't s w m 29 REVERSE FORWARD 58% m 59% m /8 REVERSE 35% L is 57FORWARD a REVERSE FORWARD REVERSE FORWARD 43% 57 /0" T .:T" 58 InventorBy W WAflor-neys United States Patent APPARATUS FOR GRINDING ORPOLISHING FLAT GLASS Robert Touvay, Paris, France, assignor toPilkington Brothers Limited, Liverpool, England, a British com- P yApplication January 25, 1951, Serial No. 207,701

4 Claims. (Cl. 51-112) This invention relates to apparatus for grinding,lapping or polishing the surface of flat glass, and which actssimultaneously in continuous progression on the two faces of acontinuous ribbon of glass, in accordance with the method knowngenerally as the continuous grind ing-polishing of two faces.

Patented J une 7, 1955 parallel with the plane of the work, and means tomove the tools transversely across the path of the work in planesparallel with the plane of the work to a position at the side of thework at which position servicing or replacement of the tools may beeffected, characterised in that the upper and lower tools of a pairare'mounted for In United States patent specification No. 2,508,863

there is described for grinding or polishing simultaneously the twofaces of a continuous ribbon of moving glass an apparatus comprisingpairs of upper and lower grinding or polishing tools, means for rotatingthe tools of each pair in planes parallel with the plane of the so thatthe positions of the upper and lower tools of a pair relative one to theotherremain unchanged and to this end the upper and lower tools of apair are mounted in a single C-shaped support arranged for movementtransversely of the direction of movement of the work in order to bringthe tools to the side of the work for the purpose mentioned above.

The construction according to the prior proposal has W:

in practice been found satisfactory when the work is of relativelynarrow width but for use in machines adapted for grinding or polishingwork pieces of greater width the apparatus is less advantageous owing tothe necessarily increased length of the arms of the C-shaped support andthe fact that the tools are carried adjacent the free ends of the arms.Accordingly for workpieces of greater width, to ensure the C-shapedsupport having adequate strength and rigidity it must be givenconsiderable proportions and weight. Further with this priorconstruction the upper and lower tools of a pair are always movedsimultaneously to the servicing position, and if only the lower tool isto be serviced or replaced it is first necessary to dismantle the uppertool.

It is a main object of the present invention to pro- 9 vide an apparatusfor grinding or polishing simultaneously the two faces of a continuousribbon of moving glass in which the tools of a pair are movableindependently one of the other to the servicing position beside the workwithout stopping the operation of the entire maf? chine.

A further object of the present invention is to permit the lower tool ofa pair to be moved to servicing position independently of the upper toolso that it can be serviced or replaced without the necessity of firstdismantling the upper tool.

According to the present invention there is provided for grinding orpolishing simultaneously the two faces of a continuous ribbon of movingglass, an apparatus comprising pairs of upper and lower grinding orpolishing tools, means to rotate the tools of each pair in planesrotation in independent supports each having traversing means associatedtherewith to effect movement of the tool transversely across the path ofthe work to said servicing position whereby the tools of a pair may be Iseparately moved to said position.

It will be readily understood that with apparatus according to thepresent invention the upper tool of a pair may be moved to servicingposition whilst the lower tool remains in position beneath the work toprovide a support for the work, this being an important feature when thework consists of a thin glass ribbon.

A further main object of the present invention is to provide anapparatus for grinding or polishing simultaneously the two sides of acontinuous ribbon of moving glass in which the rubbing action of thetools results from the rotary movement thereof and an oscilla torymovement transverse to the direction of movement of the work whichresults in the crossing, on the work, of the trajectories of each grainof abrasive material thus resulting in a substantially even grinding orpolishing and reducing or eliminating the condition known in the art asdirectional polish.

Accordingly the traversing means in apparatus according to the presentinvention may be operable to oscillate the supports in working positionalong said transverse paths whereby the grinding or polishing action ofthe tools results from the rotary and oscillatory movements thereof.

In apparatus according to the present invention the transverse movementsof the supports may be'synchronized so that the axes of rotation ofthe'tools of a pair are maintained in alignment.

In order that the invention may be clearly understood one embodimentthereof will now be described, by way of example, with reference to theaccompanying diagrammatic drawings which show the invention applied to agrinding unit and in which:

Fig. l is a view partly in section on line A--A, Fig. 2,

Fig. 2 is a plan of a part of a glass grinding machine having aratusaccording to the invention, the plan being partly in section on lineB-B, Fig. l, and

Fig.3 is a section on line C-C, Fig. 2, and shows two consecutive baysof the machine.

Fig. 4 is a circuit diagram illustrating one mode of effecting operationof electric motors employed in the apparatus.

Referring to the drawings, the grinding tools of a pair comprise a lowertool 1 and an upper tool 2, the tools being illustrated in their workingpositions with respect F to the two sides of a glass ribbon whose medianplane is represented by the lines X-Y, Fig. l, and ZZ, Fig. 3. The glassribbon is moved along the machine by rollers 3, 31, Fig. 3, the rollers,as is usual, exerting a certain pressure on the glass ribbon.

The tool 1 is mounted for rotation in a support 4 and the tool 2 issimilarly mounted in a support 5, the axes of rotation of the tools 1, 2being substantially in alignment and disposed to be normal to the planeof the work. In Fig. 3 two consecutive bays of the machine areillustrated, and in the right-hand bay the supports 41, 51, areillustrated with the tools removed therefrom in order better toillustrate the supports.

The tool 1 is mounted ina gear case 6 attached to the support 4 and thegear case carries the devices, of known construction, for regulating theposition of the tool 1 towards and away from the plane of the work,together 3 with an electric motor 7 which rotates the shaft 8 fortool 1. Similarly, the tool 2 is mounted in a gear case 9 attached tothe support and the gear case 9 also supports an electric motor 10 torotate the shaft 11 for tool 2, togethehr with the devices of knownconstruction for regulating the position of the tool 2 towards and awayfrom the plane of the world A curved metal plate 12 is movable with thesupport 4 and is provided to collect the mud containing abrasive orpolishing material which is thrown off during the course of the work andis to protect the lower mechanism against contamination by suchmaterials.

The support 4 for the lower tool 1 is provided with shoes 13, Fig. 3,which rest and slide on guide elements formed as tracks 14 forming partof angle irons 15 secured to horizontal girders 16 joining pillars 17 atopposite sides of the machine. The tracks 14 are disposed on oppositesides of the support 4 and are parallel to each other and to the planeof the work and are trans verse to the direction of movement of the workthrough the machine, being so disposed as to be normal to the directionof movement of the work.

Movement of the support along the tracks 14 is effected by an electricmotor 18 mounted on the support and transmitting motion through a chain19 to a shaft 20 provided with screw threads which mesh with a toothedwheel 21 keyed to a shaft 22. The shaft 22; is supported in bearings 23and at its ends is provided with screw threads 24 meshing with toothedWheels 25 secured to shafts 26. Secured to the shafts 26 are toothedpinions 27 which mesh with toothed racks 28 secured to the angle irons1S and extending lengthwise thereof. The gear trains connecting themotor 18 with the racks 28 are reduction trains so arranged that thetransverse movements imparted to the support 4 are slow as compared withthe rate of rotation of the tool 1 supported thereby and reversingswitches described below control the direction of rotation of the motor18 so that the support is oscillated along the tracks 14 to obtain, asdescribed above, a rubbing action of the tool which is the resultant ofthe rotary movement thereof and of the oscillatory movement in the pathtransverse to the direction of movement of the work.

When it is desired to effect servicing or replacement of the tool 1 themotor 18 is controlled in a manner such that it causes the support 4 tomove in one direction beyond its normal stroke of oscillation until thegear case 6 thereon is moved to the position 62 indicated in brokenlines in Fig. 1. During such movement, owing to the tools 1, 2 beingmounted in independent supports, the upper tool 2 remains in workingposition above the work and it is possible at the position 62 to obtainfree access to the lower tool 1 without the necessity of firstdismantling the upper tool 2. If desired when the lower tool 1 is movedto the servicing position 62 a chassis as described in the aforesaidUnited States specification No. 2,508,863 having a work supporting planemay be made to slide progressively below the work, to support the workduring the absence of the tool 1 from its working position so thatoperation of the machine can continue without interruption.

The transverse movement of the support 5 for the upper tool 2 iseffected in a manner similar to that described above with reference tothe lower tool by mechanism about to be described which operates in thesame way as that for the lower tool. To this end, an electric motor 29is mounted on the support 5 and, through a chain 30, drives a shaft 3-1,Pigv 3, provided with screw threads which mesh with a toothed wheel 32keyed to a shaft 33. The shaft 33 is supported in bearings 34 on thesupport 5 and at its ends is provided with screw threads 35 meshing withtoothed wheels 36 keyed to two vertical shafts 37. Secured to the shafts37 are toothed pinions 38 which mesh with toothed racks 39 secured tohorizontal box girders 40 connecting pillars 41 at opposite sides of themachine, the pillars 41 comprising continuations of the pillars 17mentioned above. The support 5 is provided with shoes which rest andslide on guide elements formed as tracks 42 secured to the upper facesof the box girders 40. As in the case of the motor 18, reversingswitches control the direction of rotation of the motor 29 and determinethe stroke of oscillation of the support 5 along the tracks 42.

Fig. 4 is a circuit diagram illustrating one mode of effecting operationof the motors 18, 29. The supports 4, 5 are provided respectively withpins 43, 44 normally movable by the supports in the gap formed betweenthe arms of rocking switch members 45, 46 pivoted at 47, 43respectively. The rocking members carry switch elements 49, 50 of whichthe element 49 co-operates with a forward contact 51 or a reversecontact 52 according to the direction of movement of the support 4 andthe element 50 co-operates with similar contacts 53, 54 according to thedirection of movement of the support 5.

In operation, when the supports 4, 5 are moving forward the switchelements 49, 5d engage contacts 51, 53 so that the forward contacts ofcontactors 55, 56 for motors 18, 29 are closed through solenoids 57, 58.On reaching the ends of their strokes the supports 4, 5 through pins 43,44 tip switch members 49, 59 so that contacts 52, 54 are engaged therebythus exciting solenoids 59, 6t! which in turn close the reverse contactsof contactors 55, 56, the forward contacts of which are opened ondisengagement of switch elements 49, 50 from contacts 51, 53.Accordingly the motors are reversed and the supports 4, 5 move alongtheir return stroke.

When it is desired to move a support to the servicing position thereofthis is effected by a two position, double pole, lock and free pushbutton switch 61 or 62 having one set of contacts normally open and oneset normally closed. Thus if the support 4 is to be moved to servicingposition the push button switch 61 is operated thereby cutting out theautomatic circuit and exciting solenoid 59 so that the motor 18 thenmoves the support to servicing position, the pin 43 on support 4 beingmoved away from the switch member 45. To return the support to workingposition a second push button switch 63 is pressed exciting the solenoid57 so that the motor 18 returns the support and pin to their workingpositions. A second push button switch 64, which is connected in thesame manner as push button switch 63, is provided for support 5. 1

From the foregoing it will be understood that, owing to the upper tool 2being mounted in a support 5' independent of the support 4 for the lowertool 1, when the upper tool is moved to the servicing position 52, Pig.1, the lower tool 1 remains in its working position and, accordingly,continues to support the work during servic ing of the upper tool 2, sothat operation of the machine can continue without interruption.

Usually during the operation of the pair of tools the upper and lowertool of the pair are maintained substantially in axial alignment. Ifdesired, however, the motors l8 and 29- may be so driven that duringtheir operation to effect oscillation of the supports 4, 5 along thetracks 14, 42 the movements of the supports are effected in oppositedirections. This can be etiected, as will be readily understood, by thecircuit shown in Fig. 4.

The apparatus described above comprises a preferred embodiment of theinvention but it will be understood that other ways of carrying theinvention into effect may be employed within the terms of the claimsappended hereto.

I claim:

1. Apparatus for operating on a continuously moving ribbon of glass,comprising a plurality of co-axial pairs of tools of which the tools ofeach pair co-act to operate simultaneously on the two surfaces of theribbon, pairs of driving rolls between said pairs of co-axial tools todrive the ribbon between the tools of each pair, an individualtravelling support for each tool of a pair disposing the respective toolfor rotation in a plane parallel with the path through which the ribbonis moved by the driving rolls, a first motor carried by each saidsupport to efiect operative rotation of the tool carried thereby, a pairof linear tracks individual to each said support disposed in spacedrelation to permit lateral movement of the support therebetween,traversing means carried by each support co-operating with each of therespective tracks to effect lateral movement of the support along saidtracks, a reversible second motor carrled by each said support andreduction gearing connecting the reversible motor with the traversingmeans to produce relatively slow lateral movement of the supports ascompared with the rate of rotation of the tools carried thereby.

2. Apparatus according to claim 1, wherein each track carries a toothedrack extending lengthwise of and inwards of the respective track pair,and the traversing means for each tool comprises a pair of pinionsjournalled in the respective tool support and disposed to mesh with therespective track pair, the associated reduction gear actuated by thereversible motor driving the said pair of pinions.

3. In apparatus for grinding or polishing simultaneously the twosurfaces of a continuous ribbon of glass including co-axial pairs oftools, the tools of a pair co-acting to operate simultaneously on thetwo surfaces of the ribbon and means for advancing the ribbon betweenthe co-operating pairs of tools, an individual travelling support foreach tool, a framework, pairs of parallel tracks, one pair for eachtravelling support, said tracks being fixed in the frame-work at rightangles to the direction of movement of the ribbon, a first motor carriedby each tool support to effect operative rotation of the tool,traversing means carried by each support co-operating with theassociated pair of tracks to effect lateral movement of the supportalong its pair of tracks as the respective tool rotates, a reversingmotor carried by each support and reduction gearing connecting thereversing motor with the traversing means to produce a relatively slowmovement of the support along its tracks, as compared with the rate ofrotation of the tool, and switch means for controlling the operation ofthe reversing motor.

4. Apparatus according to claim 3, wherein the pair of tracks are of alength such that each tool may traverse the ribbon in operative relationtherewith and be moved beyond the ribbon to a servicing position.

References Cited in the file of this patent UNITED STATES PATENTS1,474,672 Heuze Nov. 20, 1923 1,684,029 Howard Sept. 11, 1928 1,803,752Ford May 5, 1931 2,176,481 Waldron et al. Oct. 17, 1939 2,398,556Pearson Apr. 16, 1946 2,508,863 Labby et al. May 23, 1950

1. APPARATUS FOR OPERATING ON A CONTINUOUSLY MOVING RIBBON OF GLASS,COMPRISING A PLURALITY OF CO-AXIAL PAIRS OF TOOLS OF WHICH THE TOOLS OFEACH PAIR CO-ACT TO OPERATE SIMULTANEOUSLY ON THE TWO SURFACES OF THERIBBON, PAIRS OF DRIVING ROLLS BETWEEN SAID PAIRS OF CO-AXIAL TOOLS TODRIVE THE RIBBON BETWEEN THE TOOLS OF EACH PAIR, AND INDIVIDUALTRAVELLING SUPPORT FOR EACH TOOL OF A PAIR DISPOSING THE RESPECTIVE TOOLFOR ROTATION IN A PLANE PARALLEL WITH THE PATH THROUGH WHICH RIBBON ISMOVED BY THE DRIVING ROLLS, A FIRST MOTOR CARRIED BY EACH SAID SUPPORTTO EFFECT OPERATIVE ROTATION OF THE TOOL CARRIED THEREBY, A PAIR OFLINEAR TRACKS INDIVIDUAL TO EACH SAID SUPPORT DISPOSED IN SPACEDRELATION TO PERMIT LATERAL MOVEMENT OF THE SUPPORT THEREBETWEEN,TRAVERSING MEANS CARRIED BY EACH SUPPORT CO-OPERATING WITH EACH OF THERESPECTIVE TRACKS TO EFFECT LATERAL MOVEMENT OF THE SUPPORT ALONG SAIDTRACKS, A REVERSIBLE SECOND MOTOR CARRIED BY EACH SAID SUPPORT ANDREDUCTION GEARING CONNECTING THE REVERSIBLE MOTOR WITH THE TRAVERSINGMEANS TO PRODUCE RELATIVELY SLOW LATERAL MOVEMENT OF THE SUPPORTS ASCOMPARED WITH THE RATE OF ROTATION OF THE TOOLS CARRIED THEREBY.